1. Field of the Invention
The invention generally relates to resource allocation in a wireless communications system, and more particularly, to methods for resource allocation and related mobile communications devices, femtocells and wireless communication systems capable of performing resource allocation in a wireless communication environment where multiple femtocells interfere with each other within a coverage area.
2. Description of the Related Art
In a typical wireless communication network, the deployment of network nodes is generally planned by the operator beforehand. However, the network coverage is sometimes inevitably limited due to signal attenuation in structures, especially in indoor areas, such as home premises and office areas. A femtocell is a small cellular base station, typically designed for use in a home or small business, which allows a wireless communication network to extend network coverage indoors. To restrict the interference to other users in the macro cell, the coverage of a femtocell is far smaller than that of a macro base station. In a hybrid access network, the coverage of a macro base station may consist of a large number of femtocells. For a long term evolution (LTE) network developed by the 3rd Generation Partnership Project (3GPP) origination, a femtocell may be referred to as a Home Node-B (HNB) or a home evolved Node-B (or HeNB), and usually enhances the wireless transmission quality of the service network in the indoor environment such as homes or small commercial areas. The HNB can connect to a service provider network via a wired or wireless backhaul connection. For example, the HNBs or HeNBs are used for deployment on school campuses or are used for deployment in users' homes.
For the network architecture with the aforementioned femtocells, most of the previous technology tends to focus on the resource allocation method between the macro cell and femtocell, while ignoring the seriousness of interactive interference among the femtocells. The current resource allocation method for the interactive interference among the femtocells requires a central control system to control all the base stations, collect information from all base stations, and decide how to allocate resources. However, for an urban area with an intensive deployment of femtocells, because of the plug-and-play features of the femtocell, the number of base stations of the interactive interference may be too large, making the previous method inapplicable in an urban area with an intensive deployment of femtocells. In addition, many of the base stations need to be controlled, leading to long computation times that seriously affect the user. On the other hand, if there is no central control system, the chain effects generated by interactive interference among the femtocells may easily be ignored, resulting in more serious deterioration of system performance in an urban area of intensive deployment.